Mesoporous carbon nitride for adsorption and fluorescence sensor of N-nitrosopyrrolidine

• Mesoporous carbon nitride as a good adsorbent for N-nitrosopyrrolidine.
• Mesoporous carbon nitride as a fluorescence sensor for N-nitrosopyrrolidine.
• Terminal NC groups as favoured sites interacted with N-nitrosopyrrolidine.

A metal-free mesoporous carbon nitride (MCN) was investigated for the first time as an adsorbent for N-nitrosopyrrolidine (NPYR), which is one of the nitrosamine pollutants. Under the same condition, the adsorption capability of the MCN was found to be higher than that of the MCM-41. Since the adsorption isotherm was consistent with Langmuir and Freundlich model equations, it was suggested that the adsorption of NPYR molecules on the MCN occurred in the form of mono-molecular layer on the heterogeneous surface sites. It was proposed that MCN with suitable adsorption sites was beneficial for the adsorption of NPYR. The evidence on the interaction between the NPYR molecules and the MCN was supported by fluorescence spectroscopy. Two excitation wavelengths owing to the terminal NC and NC groups were used to monitor the interactions between the emission sites of the MCN and the NPYR molecules. It was confirmed that the intensity of the emission sites was quenched almost linearly with the concentration of NPYR. This result obviously suggested that the MCN would be applicable as a fluorescence sensor for detection of the NPYR molecules. From the Stern–Volmer plot, the quenching rate constant of terminal NC groups was determined to be ca. two times higher than that of the NC groups on MCN, suggesting that the terminal NC groups on MCN would be the favoured sites interacted with the NPYR. Since initial concentration can be easily recovered, the interactions of NPYR on MCN were weak and might only involve electrostatic interactions.

Mesoporous carbon nitride was proposed as a potential adsorbent and fluorescence sensor for N-nitrosopyrrolidine. Based on the fluorescence spectroscopy, the surface interaction between the mesoporous carbon nitride and the N-nitrosopyrrolidine molecules would involve electrostatic interactions and the favoured sites that were mainly interacted with the molecules would be the terminal NC groups.Figure optionsDownload as PowerPoint slide